M69000 Asiliant Technologies, M69000 Datasheet - Page 354

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

BitBLT Operation
E-19
does not use per-pixel write-masking, bits 16-13 should be set to 0. Bit 12 should be set to 0 to ensure that
the settings in the Monochrome Source Control Register (BR03) will have no effect on this BitBLT operation.
Bit 11 should be set to 0 to configure the BitBLT engine for a destination within the frame buffer. The setting
of bits 10-8 do not affect this BitBLT operation, since source data is not used. Therefore, these bits might
as well be set to zero as a default. Finally, bits 7-0 should be programmed with the 8-bit value of F0h to
select the bit-wise logical operation in which a simple copy of the pattern data to the destination takes place.
Selecting this bit-wise operation in which no source data is used as an input causes the BitBLT engine to
automatically forego either reading source data from the frame buffer or waiting for the host CPU to provide
it.
Bits 28-16 of the Source and Destination Offset Register (BR00) must be programmed with number of bytes
in the interval from the start of one scan line’s worth of destination data to the next. Since the color depth
is 8 bits per pixel and the horizontal resolution of the display is 1024, the value to be programmed into these
bits is 400h, which is equal to the decimal value of 1024. Since this BitBLT operation does not use source
data, the BitBLT engine ignores bits 12-0.
Bits 22-3 of the Pattern Address Register (BR05) must be programmed with the address of the pattern data.
This address is specified as an offset from the beginning of the frame buffer where the pattern data begins.
In this case, the address is 100000h.
Similarly, bits 22-0 of the Destination Address Register (BR07) must be programmed with the address of
the destination, i.e., the offset from the beginning of the frame buffer of the byte at the destination that will
be written to first. In this case, the address is 20080h, which corresponds to the byte representing the pixel
at coordinates (128, 128).
Figure E-14: Pattern Data for Example Pattern Fill BitBLT
This BitBLT operation does not use the values in the Pattern/Source Expansion Background Color Register
(BR01), the Pattern/Source Expansion Foreground Color Register (BR02), the Monochrome Source Control
Register (BR03), the Source Address Register (BR06), the Source Expansion Background Color Register
(BR09), or the Source Expansion Foreground Color Register (BR0A).
The Destination Width and Height Register (BR08) must be programmed with values that describe to the
BitBLT engine the 64x64 pixel size of the destination location. Bits 28-16 should be set to carry the value
of 40h, indicating that the destination location covers 64 scan lines. Bits 12-0 should be set to carry the
value of 40h, indicating that each scan line’s worth of destination data occupies 64 bytes. The act of writing
a non-zero value for the height to the Destination Width and Height Register (BR08) is what signals the
BitBLT engine to begin performing this BitBLT operation. Therefore, it is important that all other
programming of the BitBLT registers be completed before this is done.
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69000 Databook
Subject to Change Without Notice
Revision 1.3 8/31/98